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Wednesday, March 30, 2011

The fly family tree

Did you know there are about seventeen quadrillion flies on Earth? Neither did I. Apparently, there are some 200,000 species of true fly (insects with a single pair of wings, order Diptera). Thanks to the work of Brian Wiegmann of North Carolina State University and a large international team of entomologists and geneticists, we have a better picture of how all these flies are related to each other.

Flies have been around for 260 million years. Among other adaptations, during that time, twelve different groups of flies have taken to feeding on blood, and eighteen types of flies have lost their wings. They’ve evolved the ability to live in an amazing variety of places, either as adults or as larvae. According to Wiegmann:

There are fly larvae that live in petroleum, in hot springs, in the gills of land crabs, on the dung of millipedes and within bee hives.

The researchers compared the mitochondrial and nuclear DNA of an assortment of flies to assemble an evolutionary tree for these flies. Many of the results were expected. Flies that had been grouped together by physical traits turned out to be genetically related as well. However, there was at least one major surprise. The fruit fly Drosophila, which may be the most common animal model in all of science, turned out to be most closely related to a couple of insect parasites, including a wingless fly that lives on honeybees. Who could have seen that coming?

Thanks to the painstaking work of collecting fly samples and sequencing their DNA, we now have an understanding of how flies evolved. This in turn, gives us a better understanding of evolution in general, always a plus.